Autotomy and running performance of fiddler crabs (Decapoda: Brachyura: Ocypodidae)

Abstract The sexually dimorphic, enlarged major claw is a notorious trait among male fiddler crabs, but comes with potential locomotor costs. Possessing the ability to autotomize the enlarged claw is thus potentially advantageous to not only to escape a predator’s grip, but also to increase running performance. Previous studies concluded that autotomy either has no effect or even a negative effect on running performance. If the claw does not aid in locomotion, then shedding the enlarged claw that accounts for 40% of a fiddler crab’s mass should positively affect running performance. I therefore investigated autotomy and running performance in the Atlantic sand fiddler crab Leptuca pugilator (Bosc, 1801) with a focus on improving upon the methods of previous studies. Crabs were given substantial recovery time between collection, running trials, and autotomy induction. Maximum sprint speed was assessed by running crabs on a 1 m sand and mud track where individuals were significantly faster after autotomy of the enlarged claw (N = 64, t63=-7.25, P < 0.001). Intact running velocity was furthermore a significant predictor of autotomized running velocity (R2 = 0.194, P < 0.001). This study is the first to show a significant increase in fiddler crab sprint velocity after autotomy on a flat surface, and I propose where methodological pitfalls may have occurred in previous studies.

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Multimodal communication in courting fiddler crabs reveals male performance capacities

Royal Society Open Science ◽

10.1098/rsos.161093 ◽

2017 ◽

Vol 4 (3) ◽

pp. 161093 ◽

Cited By ~ 14

Author(s):

Sophie L. Mowles ◽

Michael Jennions ◽

Patricia R. Y. Backwell

Keyword(s):

Field Experiments ◽

Fiddler Crabs ◽

Vibrational Signal ◽

Sprint Speed ◽

Additional Signal ◽

Additional Information ◽

Waving Display ◽

Redundant Signal ◽

Strong Positive Relationship ◽

Multimodal Signalling

Courting males often perform different behavioural displays that demonstrate aspects of their quality. Male fiddler crabs, Uca sp., are well known for their repetitive claw-waving display during courtship. However, in some species, males produce an additional signal by rapidly stridulating their claw, creating a ‘drumming’ vibrational signal through the substrate as a female approaches, and even continue to drum once inside their burrow. Here, we show that the switch from waving to drumming might provide additional information to the female about the quality of a male, and the properties of his burrow (multiple message hypothesis). Across males there was, however, a strong positive relationship between aspects of their waving and drumming displays, suggesting that drumming adheres to some predictions of the redundant signal hypothesis for multimodal signalling. In field experiments, we show that recent courtship is associated with a significant reduction in male sprint speed, which is commensurate with an oxygen debt. Even so, males that wave and drum more vigorously than their counterparts have a higher sprint speed. Drumming appears to be an energetically costly multimodal display of quality that females should attend to when making their mate choice decisions.

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Booklet development based on research identification of fiddler crab (Uca spp.) diversity in mangrove ecosystem

Jurnal Pendidikan Biologi Indonesia ◽

10.22219/jpbi.v4i1.5337 ◽

2018 ◽

Vol 4 (1) ◽

pp. 61

Author(s):

Ajizatunnisa Ajizatunnisa ◽

Sri Wahyuni ◽

Lud Waluyo ◽

Fuad Jaya Miharja

Keyword(s):

Local Community ◽

Fiddler Crab ◽

Research Result ◽

Biology Education ◽

Mangrove Ecosystem ◽

Fiddler Crabs ◽

Ecological Benefits ◽

The University ◽

Self Learning ◽

Product Specifications

The purpose of this development study is to develop research-based booklet for the identification of fiddler crab (Uca spp.) diversity. Some people do not yet know the ecological benefits of fiddler crabs. This is apparent when some people take fiddler crabs to serve as decorative crabs. The product specifications expected in the development of this medium are booklets. Therefore, it takes a companion learning media that can lead the local community to implement self-learning in the form of booklet because their interest of reading is very less, especially when reading a book that is colorless and has a lot of words. Booklet that is packed with interesting and accompanied by pictures is an alternative solution. The development method used in the research is Exploration, Explanation, and Evaluate (3E) model. The research was conducted by developing the research result into a booklet based on the diversity of fiddler crabs in mangrove ecosystem. The booklet validation consists of two lecturers from the Department of Biology Education at the University of Muhammadiyah Malang which is a material expert and learning media expert. The result of this research is booklet very valid with the percentage of material expert validity 81.25% and learning media expert 95.13%.

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IDENTIFIKASI JENIS KEPITING BIOLA DI HUTAN MANGROVE DUSUN SETINGGA ASINDESA SEBUBUS KECAMATAN PALOH KABUPATEN SAMBAS

JURNAL HUTAN LESTARI ◽

10.26418/jhl.v8i1.39385 ◽

2020 ◽

Vol 8 (1) ◽

Author(s):

Edy Kurniawan ◽

M Sofwan Anwari ◽

M Dirhamsyah

Keyword(s):

Sampling Method ◽

Fiddler Crab ◽

Sandy Beaches ◽

Mangrove Forests ◽

Crab Species ◽

Fiddler Crabs ◽

Purposive Sampling ◽

Plot Size ◽

Uca Annulipes

The fiddler crab is also known as the kepiting biola is an animal that has broad legs that belong to the Crustacean class. Fiddler crab is a type of crab that has a habitat in intertidal areas, especially around mangrove forests and sandy beaches. This study aims to examine the identification of fiddler crab species found in the Mangrove Sebubus. The method used in this research is purposive sampling method with the use of a square plot size of 1 x 1 meter as many as 30 pieces in 3 research lines. The results showed as many as 7 species of fiddler crabs found there, that is Uca annulipes, Uca rosea, Uca forcipata, Uca bellator, Uca tetragonon, Uca paradussumieri, and Uca acuta.Keywords: Identification, Fiddler Crab, Mangrove Sebubus

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Thermoregulation as an Alternate Function of the Sexually Dimorphic Fiddler Crab Claw

The American Naturalist ◽

10.1086/661239 ◽

2011 ◽

Vol 178 (3) ◽

pp. 419-428 ◽

Cited By ~ 35

Author(s):

M. Zachary Darnell ◽

Pablo Munguia

Keyword(s):

Fiddler Crab ◽

Sexually Dimorphic

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KEANEKARAGAMAN KEPITING BIOLA PADA KAWASAN HUTAN MANGROVE DESA KARIMUNTING KECAMATAN SUNGAI RAYA KEPULAUAN KABUPATEN BENGKAYANG

JURNAL HUTAN LESTARI ◽

10.26418/jhl.v8i2.40332 ◽

2020 ◽

Vol 8 (2) ◽

Author(s):

Hanafi Hanafi ◽

M Sofwan Anwari ◽

Ahmad Yani

Keyword(s):

Fiddler Crab ◽

Diversity Index ◽

Species Abundance ◽

Similarity Index ◽

Sampling Technique ◽

Fiddler Crabs ◽

Species Diversity Index ◽

Transect Line ◽

Species Similarity ◽

Index Value

Karimunting Village is a coastal area that has a mangrove with contained several faunas in it, one of which is a fiddler crab. The fiddler crab is a Decapoda ordo and it is included in the Ocypodidae family. This study aims to collect data on the diversity of fiddler crabs in Karimunting Village. The method used in this study is a survey, while the sample is collected by applying the transect line with a purposive sampling technique. The transect line is 500 m length, with a total of three lanes. There are ten plots of 1x1 meter in size in each transect lines to pick up fiddler crabs. Fiddler crabs species were found in 6 species, namely Uca paradussumieri, Uca annulipes, Uca forcipata, Uca rosea, Uca crassipes and Uca tetragonon. The Shannon-Winner species diversity index (H') of fiddler crabs in 1st and 2nd lanes both are categorized medium, while in the 3rd lane is categorized low. The range of values H'=0,3-1,5. The value of species abundance index (Xi) ranges from 3-16.6 ind/m2. The value of evenness index (e) ranges from 0,72 to 0,84. The dominance index value (C) ranges from 0,3 to 0,5 categorized as the absence of the dominant species of fiddler crab. Comparison of species similarity index (IS) for each lane is categorized differently, for the 1st and 2nd lane the index is 91% and categorized as having high species similarity, then in 2nd and 3rd lane the index is 75% and categorized as having a medium species similarity, whereas the index for 1st and 3rd is 60%, therefore it is categorized as having low species similarity.Keyword: Diversity, Fiddler Crab, Karimunting Village

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ETHOLOGICAL ASPECTS OF THE FIDDLER CRAB UCA LATIMANUS RATHBUN, 1893 IN THE ESTUARY EL SALADO, PUERTO VALLARTA, JALISCO, MEXICO

BIOCYT Biología Ciencia y Tecnología ◽

10.22201/fesi.20072082e.2015.8.76148 ◽

2015 ◽

Vol 8 ◽

Author(s):

Carlos De La Cruz-Manjarrez ◽

Horacio Vázquez-López

Keyword(s):

Feed Rate ◽

Rainy Season ◽

Fiddler Crab ◽

Weather Conditions ◽

Dry Season ◽

Feeding Time ◽

Fiddler Crabs ◽

Daily Weather ◽

Sedimentary Structures

This study was conducted in the rainy (June-August 2013) and dry season (April 2014) in the El Salado estuary, Puerto Vallarta, Jalisco, Mexico to understand the behavior of fiddler crabs Uca latimanus Rathbun, 1893 by means of films. Observe behaviors were: feeding, walking (displacement), feeding and walking, standing (stationary), aggression and defense, agitation chela; the feed rate was also obtained. The temperature ranged between 29 and 38 ° C in the two seasons. In rainy season the presence of U. latimanus, mainly due to the humidity when it reaches a maximum of 80% of the land and their behavior is influenced by the daily weather conditions. The organisms spend more time feeding and shaking the chelipeds, but these do not occur simultaneously. The aggression is not only seen among males, which also attack females. U. latimanus males inhabit burrows with sedimentary structures (domed) However, not observed or if females are those who are in charge of construction. In dry season, U. latimanus lives only in small patches of marsh and flood behavior is limited to food. As to feeding time, females are twice as fast than males doing this activity at low tide. U. latimanus cohabits with Uca princeps princeps and Uca zacae, however the first presents a specific territory.

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Signals from ‘crabworld’: cuticular reflections in a fiddler crab colony

Journal of Experimental Biology ◽

10.1242/jeb.204.14.2561 ◽

2001 ◽

Vol 204 (14) ◽

pp. 2561-2569 ◽

Cited By ~ 7

Author(s):

Jochen Zeil ◽

Martin Hofmann

Keyword(s):

Fiddler Crab ◽

Video Camera ◽

The Body ◽

Ultraviolet Region ◽

High Contrast ◽

Fiddler Crabs ◽

Specular Reflections ◽

Males And Females ◽

Behavioural Repertoire ◽

Different Parts

SUMMARY Fiddler crabs inhabit intertidal sand- and mudflats, where they live in dense colonies and are active on the surface during low tide. They exhibit a rich behavioural repertoire, with frequent interactions between animals in the context of territorial and mating activities. Male fiddler crabs have one massively enlarged and conspicuously coloured claw, which they use in waving displays and in fights with other males. The crabs carry their eyes on long, vertically oriented stalks high above the body and, as a consequence, see the bodies of conspecifics in the ventral visual field, below the local visual horizon, and against the mudflat surface as background. We filmed events in a colony of Uca vomeris with a normal video camera and an ultraviolet-sensitive camera placed at the eye height of an average crab, approximately 2–3cm above ground. We also used a spectrographic imager and linear polarized filters to analyse the cues potentially available to the animals for detecting, monitoring and possibly identifying each other. Areas of high contrast in mudflat scenes include specular reflections on the wet cuticle of crabs that are horizontally polarised. Besides specular reflections, some parts of the cuticle generate high-contrast signals against the mudflat background, both at wavelengths between 400 and 700nm, and in the ultraviolet region between 300 and 400nm. Uca vomeris can be very colourful: the different parts of the large claw of the male are white, orange or red. The carapace colours of both males and females can range from a mottled yellowish green brown, to a brilliant light blue. White and blue colours contrast starkly with the mudflat background, especially in the ultraviolet wavelengths. Under stress, the blue and white colours can change within minutes to a duller and darker blue or to a dull white.

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Differences in the Use of Cheliped Autotomy by the Mud Fiddler Crab Uca Pugnax (Smith, 1870) (Decapoda, Ocypodidae) When Escaping Predation by the Blue Crab Callinectes Sapidus (Rathbun, 1896)

Crustaceana ◽

10.1163/156854011x594795 ◽

2011 ◽

Vol 84 (11) ◽

pp. 1281-1293 ◽

Cited By ~ 6

Author(s):

M. C. Curran ◽

M. M. Mace III

Keyword(s):

Blue Crab ◽

Visual Stimulus ◽

Fiddler Crab ◽

Callinectes Sapidus ◽

Large Male ◽

Effective Strategy ◽

Uca Pugnax ◽

Fiddler Crabs ◽

Significant Difference ◽

Major Cheliped

AbstractAutotomy of limbs has been observed for a variety of organisms and in some taxa has been shown to be an effective strategy for escaping predation. We investigated differences in the use of cheliped autotomy by small and large male fiddler crabs during predation events, and also assessed if autotomy of the major cheliped allowed male fiddler crabs to escape predation more often than females. The blue crab Callinectes sapidus was presented with 5 small and 5 large male mud fiddler crabs Uca pugnax (n = 60), and in a second experiment, 5 male and 5 female U. pugnax were presented to C. sapidus (n = 60). Large U. pugnax autotomized their major cheliped more often and survived compared to small U. pugnax (n = 22 pools, S = 96.5, p < 0.0001), although this difference was not significant when adjusted for the total number of attacks on each size (n = 22 pools, S = 45, p = 0.1467). There was no significant difference (n = 29 pools, S = 30.5, p = 0.4988) between the total number of unsuccessful attacks on male versus female U. pugnax. At least half of the males autotomized their major cheliped in unsuccessful attacks during the first (69%) and second (53%) experiments. The major cheliped of male U. pugnax is a prominent visual stimulus that may have initially attracted C. sapidus to this prey; however, autotomization potentially enabled male fiddler crabs to escape predation in over half of all unsuccessful attacks.

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Differences in proportional claw size among left- and right-handed Atlantic sand fiddler crabs Leptuca pugilator (Bosc, 1801) (Decapoda: Brachyura: Ocypodidae)

Journal of Crustacean Biology ◽

10.1093/jcbiol/ruz067 ◽

2019 ◽

Vol 39 (6) ◽

pp. 720-723

Author(s):

Benjamin E Martin

Keyword(s):

Body Size ◽

The Body ◽

Sexually Dimorphic ◽

Evolutionary Perspective ◽

Prominent Feature ◽

Body Proportions ◽

Fiddler Crabs ◽

Sexual Signal ◽

Right Hand ◽

Left And Right

Abstract The sexually dimorphic, enlarged major claw is a prominent feature among fiddler crabs and acts as both a sexual signal and weapon. Most often the enlarged claw occurs on the left and right sides of fiddler crabs in relatively even proportions (40–60%), but populations exhibit an extreme right handedness bias (> 90%) in a few cases. The mechanisms maintaining relatively even handedness proportions among fiddler crabs remains debatable, but from an evolutionary perspective it should be maintained through an evenness in fitness (reproduction and survival) between left- and right-handed crabs. I investigated handedness ratios and claw to body size in a Leptuca pugilator (Bosc, 1801) population on Sapelo Island, Georgia, USA. In collecting 417 adult male crabs, there was a slight right-hand bias (54%, χ 2= 2.9376, P = 0.087), which was similar to the previous study of this population 17 years prior. I nevertheless found right-handed crabs had significantly smaller claw size relative to their carapace size (P = 0.018). Overall, this study documents inequality in the body proportions between left- and right-handed L. pugilator within a population operating at a slight right hand-bias. I discuss how my study contributes to previous discussions on handedness bias in fiddler crabs as well as potential mechanisms that control its widespread handedness evenness.

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Not what it looks like: mate-searching behaviour, mate preferences and clutch production in wandering and territory-holding female fiddler crabs

Royal Society Open Science ◽

10.1098/rsos.160339 ◽

2016 ◽

Vol 3 (8) ◽

pp. 160339 ◽

Cited By ~ 5

Author(s):

M. Peso ◽

E. Curran ◽

P. R. Y. Backwell

Keyword(s):

Mate Choice ◽

Fiddler Crab ◽

Female Mate Choice ◽

Mate Preferences ◽

Fiddler Crabs ◽

Mate Searching ◽

Searching Behaviour ◽

Female Mate ◽

Predator Behaviour

Risks inherent in mate-searching have led to the assumption that females moving sequentially through populations of courting males are sexually receptive, but this may not be true. We examined two types of fiddler crab females: wanderers moving through the population of courting males and residents that were occupying and defending their own territories. Sometimes residents leave territories to look for new burrows and we simulated this by displacing wanderers and residents and observing their behaviour while wandering. We predicted that the displaced wanderers would exhibit more mate-searching behaviours than resident females. However, wandering and resident females behaved nearly identically, displaying mate-searching behaviours and demonstrating matching mate preferences. Also, males behaved the same way towards both female types and similar proportions of wanderers and residents stayed in a male's burrow to mate. But more wanderers than residents produced egg clutches when choosing a burrow containing a male, suggesting females should be categorized as receptive and non-receptive. Visiting and rejecting several males is not the defining feature of female mate choice. Moving across the mudflat by approaching and leaving a succession of burrows (mostly occupied by males) is an adaptive anti-predator behaviour that is useful in the contexts of mate-searching and territory-searching.

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